One of the sharpest cold fronts in recent years tore across the central and eastern U.S. this past weekend, leaving millions of Americans shivering in its wake.
Packing wind chills below -50°F at times, the cold punch was a fitting climax to more than a week of off-and-on chill over large parts of the northern U.S. Extreme temperature contrasts were the norm with this front: for example, noontime readings across Georgia on Sunday ranged from 37°F with rain at Dalton, in the far north, to 83°F at Albany, in the far south. More than 1000 flights were cancelled on Friday and Saturday as bursts of snow struck in and near Denver and Chicago and a brief, high-impact round of freezing rain hit parts of the mid-Atlantic early Saturday morning. A
horrifying 67-vehicle crash on ice-glazed I-95 in Baltimore, MD, killed two and injured more than 20 others, at least two in critical condition.
Figure 1. Darryl Hendricks moves into position on a breakwater to photograph sea smoke rising off the waters of Casco Bay, Maine, on Friday, Dec. 16, 2016, in South Portland. Hendricks risked both frostbite and being late for work in pursuit of what he called "the one shot I really wanted." The temperature dropped to -2°F with a wind chill of -25°F. Image credit: AP Photo/Robert F. Bukaty.
Figure 2. Pedestrians walk across a snowy street in downtown Kansas City, Missouri, on Saturday, Dec. 17, 2016. Image credit: AP Photo/Charlie Riedel.
A Texas-sized temperature swingGrand prize for the most dramatic frontal passage goes to West Texas, where the cold air mass plowed south on Saturday in the form of a classic “
blue norther” (sometimes called a Texas norther). A mesonet station about 6 miles west of Denver City, TX, reported a temperature drop of 36°F in just 10 minutes--from 21°C (70°F) to 1°C (34°F)--accompanied by winds of 40 knots (46 mph) gusting to 69 knots (79 mph). Thanks to Anton Seimon (Appalachian State University) for finding this nugget.
Temperatures across Texas at 4:00 pm CST Saturday ranged from 6°F at Dumas (nearby Dalhart sank to a record-low –8°F by Sunday morning) to a record-hot 92°F at McAllen. Midland set a record high of 80°F on Saturday afternoon, but by 11:59 pm CST, the city’s official temperature had plummeted to 18°F, just one degree short of the day’s record low! It was Midland's
biggest one-day temperature spread for any date in records going back to 1930. More than a century ago,
a blue norther on November 11, 1911 (11/11/11) managed to pull off the twin-record-in-one-day trick in both Oklahoma City, OK (83°F and 17°F) and Springfield, MO (80°F and 13°F). Both of these Oklahoma City records still stand.
Figure 3. In Big Lake, Texas, about 50 miles southeast of Midland, temperatures sank from around 80°F at 4:00 pm CST Saturday to near freezing by 6:00 pm and below 20°F by midnight. Times are shown for a 24-hour clock (15 = 1500 CST = 3:00 pm CST). Because the lower atmosphere was so well mixed on this day, the temperature traces are virtually identical at the indicated heights above ground of 1.5, 2, and 9 meters (roughly 4.9, 6.6, and 29.5 feet). Image credit:
West Texas Mesonet, Texas Tech University.
Figure 4. It’s not hard to find the frontal boundary across the south-central U.S. in this model analysis from 18Z (noon CST) Saturday, December 17, 2016. Image credit:
www.tropicaltidbits.com.
Serious cold in the nation’s heartlandReadings well below -20°F were scattered across the central and northern Great Plains into the Upper Midwest, and a few spots notched their coldest single night in many decades. Watertown, SD, dipped to -37°F on Sunday morning, just 3°F shy of its all-time low of -40°F (January 13, 1916). The reading smashed Watertown’s daily record of -24°F from 1983 and set a new monthly record for December. Data in Watertown goes back to 1893. In Limon, CO, a December record was also set, and an all-time record for any month tied, as the temperature bottomed out at -27°F before midnight Saturday. Limon’s climate data begins fairly recently, though, in 1970.
If it’s any comfort, many folks in Florida are ready for a touch of relief after a summerlike weekend of high humidity and temperatures soaring as high as 90°F. Miami’s low on Sunday was a balmy 79°F, tying the monthly record-warm minimum set on Dec. 2, 1901, and the day's average temperature of 82.5°F
was a record for any December day since weather records began in Miami in 1892. Several other locations set daily record highs over the weekend across the South, even as daily record lows were being toppled just a few hundred miles to the north. We’ll see how the totals of record highs and lows stack up once the extreme pattern of this past weekend segues into a less-amplified setup this week.
Jeff Masters will be back later today with a roundup of November’s global climate.
Bob Henson